Hello Good Evening,
You seems not a pregnant, because you had a period after your unprotected sex.
Following clues help to find that you are not pregnant:
1. You had unprotected sex just 4 days before your period due date, it is very rare to conceive at that time.
2. You got a menstrual period after sex, which totally rule out your pregnancy
3. You had 3 days bleeding in menstrual bleeding, which is absolutely normal (usually normal range of bleeding 3-5 days but can be 2-7 days).
4. White mucus discharge can be suggestive of any infection or leukorrhoea.
5. You feel sleepy and dizzy, might be related to any other medical reasons.
So be relaxed, you are not pregnant, since you had a period after your unprotected sex.
If you are not agree then go for a urine pregnancy test.
Dr. Naresh Jain.